JP7653852B2 - Guide member for joining concrete precast members and joining method for concrete precast members - Google Patents

Description

The present invention relates to a guide member used when joining concrete precast members such as bridge decks, and a method for joining concrete precast members using the same.

Traditionally, in bridge and other deck replacement work, concrete precast decks manufactured in factories or on-site yards have been used to shorten construction times. Various joint structures have been proposed and put into practical use to connect these concrete precast decks.

In a previous application (Patent Document 1 below), the applicant disclosed a joint structure for joining concrete precast members, as follows:
A female joint consisting of a groove-shaped engagement portion having a groove-shaped cross section in a plan view and a female joint anchor portion extending to the rear of the groove-shaped engagement portion is embedded in the joint end surface of the concrete precast member on one side of the joint portion at a predetermined interval in the horizontal direction with the vertical groove facing the outside,
A male joint is embedded in the joint end surface of the other side of the joint at a predetermined interval in the horizontal direction on the joint end surface of the concrete precast member. The male joint anchor portion has a tip that protrudes outward, and a fixing portion that can be inserted into the groove-shaped engagement portion provided at the tip of the male joint anchor portion.
The female joint of the concrete precast member on one side is engaged with the male joint of the concrete precast member on the other side to join the concrete precast members together, and grout material is filled in the internal space of the groove-type engaging portion, the upper space and/or the lower space of the groove-type engaging portion, and in the gaps between the concrete precast member on one side and the concrete precast member on the other side,
A joint structure was proposed in which the groove-type engagement portion is formed in a vertically elongated shape that is long in the vertical direction, the fixing portion is formed in a vertically elongated shape that is long in the vertical direction, and the male joint anchor portion is formed in a flat shape that follows a vertical plane.

Patent application No. 2019-151217

In the joint structure described in Patent Document 1, the male joint of the trailing deck is fitted into the female joint of the preceding deck as it is lowered by a crane. However, the margin between the female and male joints is small, at 10 to 20 mm, and if such joints are placed at a pitch of 300 to 600 mm along the joint end surface, a total of 20 to 40 joints will be required for a deck that is 12 m wide, which creates the following problems:

The margin between the female and male joints is small, and many such joints are provided along the joint end surface, so aligning the female and male joints when mating them takes time, reducing workability.

When inserting the male joint protruding from the deck into the female joint, there is a risk of the parts deforming or breaking due to a collision between the two. In addition, there is a risk of the surface protective film made of epoxy resin, etc., applied to each joint to improve its durability peeling off, raising concerns about a decline in quality.

In addition, because there are many joints at the joint end faces between the deck slabs, many workers are required to adjust the position for the lifting and lowering work, which increases the risk of accidents such as workers getting their hands and feet caught, reducing work safety.

The main objective of the present invention is to provide a guide member for joining concrete precast members and a method for joining concrete precast members that allows for quick alignment without compromising quality when installing concrete precast members, and that allows work to be performed safely.

In order to solve the above problems, the present invention relates to a guide member used when joining concrete precast members, the guide member comprising:
The concrete precast members are embedded in the joint end surface of the concrete precast members on one side of the joint portion at a predetermined interval in the horizontal direction, with the vertical grooves facing the outside, the female joint being composed of a groove-shaped engagement portion having a groove-shaped cross section in a plan view and a female joint anchor portion extending to the rear of the groove-shaped engagement portion,
A male joint is embedded in the joint end surface of the other side of the joint at a predetermined interval in the horizontal direction on the joint end surface of the concrete precast member. The male joint anchor portion has a tip that protrudes outward, and a fixing portion that can be inserted into the groove-shaped engagement portion provided at the tip of the male joint anchor portion.
The guide member for joining concrete precast members is characterized in that the guide member is arranged opposite a concave guide member having a guide groove extending in the vertical direction, and a convex guide member having a guide protrusion that can engage with the guide groove and move along the guide groove, at a position on the joining end face of the concrete precast members where the female joint and male joint are not located.

In the invention described in claim 1, a concave guide member with a guide groove extending in the vertical direction and a convex guide member with a guide protrusion that can engage with the guide groove and move along the guide groove are arranged opposite each other at a position on the joint end surface of the concrete precast member where the female joint and male joint are not located. Therefore, when the fixing part of the male joint is inserted into the groove-type engaging part of the female joint while lowering the following concrete precast member, the guide protrusion of the convex guide member is guided along the guide groove of the concave guide member, making it easy to align the following concrete precast member. Therefore, even if the clearance between the groove-type engaging part of the female joint and the fixing part of the male joint is small, the deterioration of workability is suppressed, and the effect of shortening the construction period is expected.

In addition, the guide members do not directly contact the female and male joints to guide them, but are provided at a position on the joint end surface of the concrete precast component where the female and male joints are not located. This means that the guide members do not directly contact the female and male joints, preventing them from colliding with the guide members. In addition, because the guide members are guided by the engagement between each other, the female and male joints are prevented from colliding with each other. This eliminates the risk of deformation or damage to the joints, and the surface protective film applied to the surface of each joint does not peel off, maintaining the quality of the structure and preventing a decrease in durability.

Furthermore, because the concrete precast components are lowered while being guided by the engagement between the concave guide member and the convex guide member, fewer workers are required to adjust the position, reducing the risk of accidents and allowing the work to be carried out safely.

The present invention according to claim 2 provides a guide member for joining concrete precast members according to claim 1, in which the concave guide member and the convex guide member are provided at both ends in a direction along the joining end surface of the concrete precast members.

In the invention described in claim 2 above, the concave guide member and the convex guide member are placed at two locations, one at each end in the direction along the joint end surface of the concrete precast member, and not in the middle, which shortens the time required for alignment and allows the work to be performed safely.

The present invention according to claim 3 provides a guide member for joining concrete precast members according to claims 1 and 2, in which the vertical engagement length A between the guide groove of the concave guide member and the guide protrusion of the convex guide member is set to be greater than the vertical engagement length B between the groove-type engagement portion of the female joint and the fixing portion of the male joint.

In the invention described in claim 3, the vertical engagement length A between the guide groove of the concave guide member and the guide protrusion of the convex guide member is set to be greater than the vertical engagement length B between the groove-type engagement portion of the female joint and the fixing portion of the male joint. Therefore, when joining concrete precast members while lowering the following concrete precast member, the concave guide member and the convex guide member engage first, and then, guided by these guide members, the fixing portion of the male joint is inserted into the groove-type engagement portion of the female joint. Therefore, the following concrete precast member is reliably guided by the engagement of the guide members, the time required to align the female joint and the male joint can be shortened, and collisions between them can be prevented.

The present invention according to claim 4 provides a guide member for joining concrete precast members according to any one of claims 1 to 3, in which the gap between the guide groove of the concave guide member and the guide protrusion of the convex guide member is large at the beginning of their engagement and gradually becomes smaller as the amount of their engagement increases.

In the invention described in claim 4 above, the gap between the guide groove of the concave guide member and the guide protrusion of the convex guide member is large at the beginning of their engagement and is formed so as to gradually become smaller as the degree of their engagement increases, making it easier for the guide members to engage with each other and easier for the female and male joints to be positioned in the center.

The present invention according to claim 5 provides a guide member for joining concrete precast members according to any one of claims 1 to 4, in which the guide member installed on the concrete precast member on one side extends upward from the concrete precast member.

In the invention described in claim 5 above, the guide member installed on the concrete precast member on one side is arranged to extend above the concrete precast member, so that the concave guide member and the convex guide member reliably engage in advance, and the female joint and the male joint engage in a state in which the concrete precast member is guided by the engagement of these guide members.

According to a sixth aspect of the present invention, there is provided a method for joining concrete precast members using the guide member according to any one of the first to fifth aspects, comprising the steps of:
A method for joining concrete precast members is provided, characterized in that the guide convex portion of the convex guide member is engaged with the guide groove of the concave guide member, while the fixing portion of the male joint is inserted into the groove-type engaging portion of the female joint, thereby joining the concrete precast members to each other, and then the concave guide member and the convex guide member are removed, and grout material is filled into the internal space of the groove-type engaging portion, the upper space and/or the lower space of the groove-type engaging portion, and the gap between the concrete precast member on one side and the concrete precast member on the other side.

As explained above in detail, the present invention makes it possible to quickly align concrete precast components without compromising quality, and also allows the work to be carried out safely.

FIG. 2 is a plan view showing concrete precast decks 1A and 1B. This is a cross-sectional view taken along line II-II. FIG. 3 is a cross-sectional view taken along line III-III of FIG. FIG. This is a cross-sectional view taken along the line VV in FIG. 4. VI-VI cross-sectional view of FIG. 1. FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 1 shows a female joint 3, (A) is a front view, (B) is a plan view, (C) is a left side view, (D) is a right side view, and (E) is an E-E cross-sectional view of (B). FIG. 4 is an oblique view of the deck showing the male joint 4. 1 shows a male connector 4, in which (A) is a front view, (B) is a plan view, (C) is a left side view, and (D) is a right side view. FIG. This is a cross-sectional view of Figure 11 along XII-XII. 1A, 1B, and 1C are a front view, a plan view, and a side view, respectively, showing a concave guide member 21. FIG. 1A is a front view of a convex guide member 22, FIG. 1B is a plan view, and FIG. 1C is a side view. This is a procedure diagram for joining precast deck slabs (part 1). This is a procedure diagram for joining precast deck slabs (part 2). This is a procedure diagram for joining precast deck slabs (part 3). FIG. 11 is a cross-sectional view of a guide member according to a second embodiment. 11A, 11B, and 11C show a concave guide member 21' according to a second embodiment, in which (A) is a front view, (B) is a plan view, and (C) is a side view. This is a procedure diagram for joining precast deck slabs.

The following describes in detail the embodiments of the present invention with reference to the drawings.

The present invention is a guide member used when joining concrete precast decks (hereinafter simply referred to as precast decks). When a mechanical joint structure is used to join precast decks, compared to conventional loop joints and streamlined joints, labor is saved because the installation of reinforcing bars in the interfacial area is eliminated, and the construction period can be significantly shortened by reducing the amount of interfacial material used. However, there are drawbacks, such as the joints themselves being expensive, resulting in high construction costs, and the need for high accuracy in alignment. Therefore, the present invention proposes a guide member that is excellent in workability for alignment by installing guide members on the leading and trailing precast decks, and suspending the trailing precast deck while engaging these guide members.

(Joint structure)
First, the joint structure for joining precast decks will be described. Specifically, as shown in Figures 1 to 3, female joints 3 each consisting of a groove-shaped engagement portion 6 having a groove-shaped cross section in a plan view and a female joint anchor portion 7 extending behind it are embedded in the joint end surface of precast deck 1A on one side of joint portion 2 at a predetermined interval in the horizontal direction (perpendicular to the bridge axis) with the vertical groove 5 facing outward. Male joints 4 each consisting of a male joint anchor portion 9 with a tip protruding outward and a fixing portion 8 at the tip of the male joint anchor portion 9 that can be inserted into the groove-shaped engagement portion 6 of the female joint 3 are embedded in the joint end surface of precast deck 1B on the other side of joint portion 2 at a predetermined interval in the horizontal direction.
As shown in Figures 4 to 7, the female joint 3 of the precast deck 1A on one side is engaged with the male joint 4 of the precast deck 1B on the other side, that is, the fixing portion 8 of the male joint 4 is inserted into the groove-shaped engagement portion 6 of the female joint 3 to join the two decks, and grout material 18 is filled in the internal space IS of the groove-shaped engagement portion 6, the upper space US of the groove-shaped engagement portion 6, and the gap portion M between the precast deck 1A on one side and the precast deck 1B on the other side.

This will be explained in more detail below.
First, the female joint 3 provided on the precast deck 1A on one side will be described in detail with reference to Figs. 4 to 8.

As shown in detail in FIG. 8, the female joint 3 is a metal member that is composed of a groove-shaped engagement part 6 having a groove-shaped cross section in a plan view, with a vertical groove 5 formed on the front end face, and a female joint anchor part 7 that extends rearward from the end face of the groove-shaped engagement part 6 that faces the end face on which the vertical groove 5 is formed.

The groove-type engagement portion 6 has an open top surface and is box-shaped with the vertical groove 5 formed on the front surface in the up-down direction, communicating with the open top surface. The bottom surface of the groove-type engagement portion 6 may be open in the same way as the top surface, but it is preferable to provide a bottom plate that closes the bottom, as shown in Figure 8 (E), to give the groove-type cross section a bottomed shape. This makes it possible to prevent the groove-type engagement portion 6 from opening on both sides. In addition, an opening (not shown) for communication with the filling may be provided in the center of the bottom surface of the groove-type engagement portion 6.

The groove-shaped engagement portion 6 is formed in a vertically elongated shape. That is, the height H in the front view shown in FIG. 8(A) is greater than the width W and depth C in the plan view shown in FIG. 8(B). The height H of the groove-shaped engagement portion 6 is preferably 1.2 to 3 times, and more preferably 1.5 to 2 times, the width W or depth C. The height H of the groove-shaped engagement portion 6 is preferably 50 to 90%, and more preferably 60 to 80%, of the thickness of the precast deck 1A, and is preferably located approximately in the center of the thickness of the precast deck 1A.

As shown in FIG. 8, the width dimension W of the groove-type engagement portion 6 is approximately 80 to 150 mm, preferably 100 to 130 mm, and the depth dimension C is preferably equal to or less than the width dimension W, approximately 60 to 120 mm, preferably 70 to 100 mm.

As shown in Figure 8 (D), the width S of the vertical groove 5 formed in the groove-type engagement portion 6 is 20 to 60 mm, preferably 30 to 50 mm, and is 110 to 220%, preferably 120 to 200%, of the thickness of the male joint anchor portion 8 constituting the male joint 4 described below. It is desirable to set this ratio to the thickness of the male joint anchor portion 8 in an appropriate numerical range, since it is closely related to the allowable range of manufacturing errors or construction errors. Also, if this ratio is too large, the engagement with the fixed portion 8 of the male joint 4 will be small, decreasing the joint strength, so it is desirable to form it at a specified ratio.

The vertical groove 5 may be formed to penetrate vertically from the upper edge to the lower edge of the groove-type engagement portion 6, but as shown in FIG. 8, it is preferable to form a U-shaped vertical groove that extends from the upper edge to partway downward. By connecting the lower end as a U-shaped vertical groove, it is possible to prevent the vertical groove 5 from opening on both sides. In addition, the vertical groove 5 may be formed to have a substantially equal width over its entire length as shown in FIG. 8(D), or, although not shown, a sloping portion may be provided at the upper end of the vertical groove 5, in which the groove width gradually increases toward the top.

As shown in Figures 4 and 5, when the precast deck 1A on one side and the precast deck 1B on the other side are joined, the male joint anchor part 8 protruding from the joint end surface of the precast deck 1B on the other side is inserted into the vertical groove 5, and the fixing part 8 provided at the tip of the male joint anchor part 8 is inserted into the internal space of the groove-type engagement part 6.

The female joint anchor portion 7 extending rearward from the groove-type engagement portion 6 is preferably formed in a flat plate shape along a vertical plane as shown in FIG. 8. The female joint anchor portion 7 extends rearward a predetermined length from the center of the wall surface facing the wall surface on which the vertical groove 5 of the groove-type engagement portion 6 is formed. The rear end of the female joint anchor portion 7 is provided with rear end fixing portions 7a that protrude on both sides and are formed in a flat plate shape along a plane parallel to the joining end surface.

The height dimension of the female joint anchor portion 7 is preferably formed to be approximately equal throughout its entire length, and is 30 to 100%, preferably 40 to 60%, of the height H of the groove-type engagement portion 6.

The female joint anchor part 7 is preferably arranged independently of the bridge axis direction reinforcing bars 15 arranged on the precast deck 1A. In other words, the stress in the bridge axis direction acting on the female joint 3 is substantially supported only by the female joint anchor part 7, and does not act on the bridge axis direction reinforcing bars 15. In this way, by providing the female joint anchor part 7 independently of the bridge axis direction reinforcing bars 15, the design freedom can be improved in the arrangement of the bridge axis direction reinforcing bars 15, and when connecting to the bridge axis direction reinforcing bars 15, application to curved or inclined reinforcing bars is difficult, but in the case of the female joint 3 according to the present invention, which is arranged independently of the reinforcing bars, application is possible as long as it does not interfere with the adjacent reinforcing bars.

The length of the female joint anchor part 7 in the bridge axis direction should be 1.2 to 3 times, preferably 1.5 to 2 times, the depth C of the groove-type engagement part 6, and does not need to be provided over the entire length of the precast deck 1A in the bridge axis direction. In this way, since the female joint anchor part 7 is short and is not connected to the bridge axis direction rebar 15, it is easy to handle when manufacturing the precast deck 1A, and handleability is good.

To place the female joint 3 on one side of the precast deck 1A, as shown in Figures 4 and 5, the groove-type engagement portion 6 is embedded with the opening on the top surface and the vertical groove 5 facing the outside from the joint end surface, and the female joint anchor portion 7 is placed in a state where it is completely embedded inside the body of the precast deck 1A.

The female joint 3 is preferably manufactured by a metal mold casting method, which allows for a high degree of freedom in shape. This allows the groove-shaped engagement portion 6 and the female joint anchor portion 7 to be integrally formed, and by integrating the joint portion body and the anchor portion without welding, crimping, or bolting, the structure is stabilized and there is no risk of fatigue damage, resulting in a high-strength joint structure and facilitating the manufacture of the precast deck 1A. Furthermore, by manufacturing it by metal mold casting, the adhesion strength with the concrete is increased, improving the fixation of the female joint 3.

Next, the male joint 4 provided on the other precast deck 1B will be explained with reference to Figures 4 to 6, 9 and 10.

As shown in detail in Figures 9 and 10, the male joint 4 is a metal member that is composed of a male joint anchor part 9 whose tip end protrudes from the joint end surface of the precast deck 1B and whose base end is embedded in concrete, and a fixing part 8 that is provided at the protruding tip of the male joint anchor part 9 and can be inserted into the groove-type engagement part 6 of the female joint 3.

The fixing portion 8 is a wide portion that protrudes on both sides from the male joint anchor portion 9 in the plan view shown in FIG. 10(B), and is formed so that it can be inserted downward from the top opening into the internal space of the groove-type engagement portion 6 of the female joint 3.

The fixing portion 8 is formed in a vertically elongated shape. That is, the height K of the fixing portion 8 in the front view shown in FIG. 10(A) is greater than the width D of the fixing portion 8 in the plan view shown in FIG. 10(B). The height K of the fixing portion 8 is preferably 60-90%, and more preferably 70-80%, of the height H of the groove-shaped engagement portion 6, and should be positioned approximately in the center of the groove-shaped engagement portion 6 in the vertical direction when the precast decks 1A and 1B are joined, as shown in FIG. 5.

The width D of the fixing portion 8 is formed to be approximately equal over the entire length in the vertical direction, and is formed so that it has approximately equal protruding widths from both sides of the male joint anchor portion 9 extending rearward. The width D of the fixing portion 8 is formed to be larger than the width S of the vertical groove 5 formed in the groove-type engagement portion 6, and as shown in FIG. 6, when the fixing portion 8 is inserted into the groove-type engagement portion 6, there is an overlap U between both sides of the fixing portion 8 and both sides of the vertical groove 5 in the direction perpendicular to the joint end surface (bridge axis direction). Since this overlap U is formed over the entire length of the fixing portion 8 in the height direction, the engagement area between the female joint 3 and the male joint 4 is increased, and the joint strength between the female joint 3 and the male joint 4 can be increased.

The male joint anchor portion 9 extending rearward of the fixing portion 8 is formed in a flat plate shape along a vertical plane. One end of the male joint anchor portion 9 made of such a flat plate shape protrudes from the joint end surface of the other precast floor slab 1B and is connected to the center of the width direction of the fixing portion 8 along the vertical direction, and the other end is disposed in a state where it is embedded inside the body of the other precast floor slab 1B. At the rear end of the male joint anchor portion 9, a rear end fixing portion 9a made of a flat plate shape along a plane parallel to the joint end surface is provided, protruding on both sides in a plan view as shown in FIG. 10(B).

The male joint anchor part 9 and the fixing part 8 are preferably formed so that the height of the male joint anchor part 9 and the height of the fixing part 8 are approximately equal at the connection part, and the upper and lower ends of both are approximately aligned. This allows the stress acting on the fixing part 8 to be borne approximately evenly by the entire male joint anchor part 9.

In the embodiment shown in FIG. 10(A), the height of the male joint anchor part 9 is relatively small from the middle part to the rear. The ratio of the height of the rear part, which is formed with a relatively small height, to the height of the front part, which is formed with a relatively large height, is 40 to 80%, preferably 55 to 75%. When changing the height, if a step part where the height changes suddenly is provided, stress will concentrate there and cause damage, so it is preferable to provide an inclined part 9b where the height changes gradually as in the illustrated example. The gradient of this inclined part 9b is 30% or less, preferably 20% or less, in the direction in which the male joint anchor part 9 extends. The inclined part 9b may be provided at either the upper or lower end of the male joint anchor part 9, but it is preferable to form a tapered shape by providing it at both the upper and lower end edges as in the illustrated example. The inclined portion 9b is preferably formed in the portion of the male joint anchor portion 9 that is embedded in the concrete of the precast floor slab 1B, and in the portion that protrudes from the joint end surface, it is preferable to form it at a constant height that is approximately the same as the height K of the fixing portion 8. On the other hand, although not shown, the male joint anchor portion 9 may be formed to have an approximately uniform height over its entire length. This can further increase the fixing strength of the male joint anchor portion 9. In this case, the fixing portion 8 and the rear end fixing portion 9a connected to the front end edge and rear end edge of the male joint anchor portion 9 are preferably formed at approximately the same height as the height of the male joint anchor portion 9.

The plate thickness T of the male joint anchor portion 9 may be formed to be approximately constant over its entire length, or may be varied. In either case, it is formed to be smaller than the width S of the vertical groove 5 of the groove-type engagement portion 6.

The male joint 4 may be manufactured by joining steel plates by welding or the like, but it is preferable to manufacture it by metal mold casting, which allows for greater freedom in shape. By manufacturing it by metal mold casting, the fixing portion 8 and the male joint anchor portion 9 can be integrally formed, and by integrating the joint portion body and the anchor portion without welding, crimping, or bolting, the structure is stabilized and there is no risk of fatigue damage, resulting in a high-strength joint structure and facilitating the manufacture of the precast deck 1B. Furthermore, by manufacturing it by metal mold casting, the adhesion strength with concrete is increased, improving the fixation of the male joint 4.

(Guide member)
Next, the guide member will be described with reference to Figures 11 to 14. The guide member is attached to the joint end surfaces of the precast floor slabs 1A, 1B when joining the precast floor slabs 1A, 1B together. The joint end surfaces of the precast floor slabs 1A, 1B refer to the opposing concrete surfaces in the gap portion M between the precast floor slabs 1A, 1B when the female joint 3 and male joint 4 are engaged to bring the precast floor slab 1A on one side and the precast floor slab 1B on the other side into opposition.

Specifically, the guide members are arranged in opposition to each other at the joint end surfaces of the precast floor slabs 1A and 1B at positions where the female joint 3 and male joint 4 are not arranged, with a concave guide member 21 having a guide groove 23 extending in the vertical direction and a convex guide member 22 having a guide protrusion 24 that engages with the guide groove 23 and can move along the guide groove 23. The concave guide member 21 is fixed to one of the precast floor slabs 1A and 1B, and the convex guide member 22 is fixed to the other. In the illustrated example, the concave guide member 21 is fixed to the precast floor slab 1A on one side, and the convex guide member 22 is fixed to the precast floor slab 1B on the other side, but the convex guide member 22 may be fixed to the precast floor slab 1A on one side, and the concave guide member 21 may be fixed to the precast floor slab 1B on the other side.

To explain each member in more detail, as shown in Figure 13, the concave guide member 21 is arranged along the joint end surface of the precast deck 1A on one side, and is configured to include a member with a generally L-shaped cross section consisting of a guide surface portion 21a with the guide groove 23 formed on its outer surface, and a fixing surface portion 21b extending perpendicularly from the upper end of the guide surface portion 21a, arranged along the upper surface of the precast deck 1A on one side, and having a fixing portion formed with respect to the precast deck 1A. One example of such a member is a general-purpose angle iron (angle).

On the outer surface of the guide surface portion 21a, plate materials 25, 25 are stacked and fixed on both sides of the vertical center line CL, each extending over almost the entire length in the vertical direction, and the guide groove 23 is formed by the spaced apart portions of these plate materials 25, 25. The plate materials 25 are fixed to the outer surface of the guide surface portion 21a by known joining means such as welding or adhesive.

On the other hand, as shown in FIG. 12, the fixing surface portion 21b has one or more through holes 21c through which the anchor bolt 30 protruding from the upper surface of the precast deck 1A on one side can be inserted. The concave guide member 21 is fixed to the precast deck 1A on one side by inserting the upper end of the anchor bolt 30 through the through hole 21c and then screwing a nut from above.

As shown in FIG. 12, a spacer 31 of a specified thickness is placed between the fixed surface portion 21b and the precast deck 1A on one side to prevent interference between the corner of the concave guide member 21 made of angle iron and the corner of the precast deck 1A.

As shown in FIG. 14, the convex guide member 22, like the concave guide member 21, is arranged along the joint end surface of the other precast deck 1B and is configured to include a member with a generally L-shaped cross section, which includes a guide surface portion 22a on whose outer surface the guide convex portion 24 is formed, and a fixing surface portion 22b extending perpendicularly from the upper end of the guide surface portion 22a, arranged along the upper surface of the other precast deck 1B, and on which a fixing portion for the precast deck 1B is formed, as shown in FIG. 14. As an example of such a member, a general-purpose angle iron is preferably used.

On the outer surface of the guide surface portion 22a, a convex member 26 that forms the guide convex portion 24 is stacked and fixed on the vertical center line CL. In the illustrated example, the convex member 26 is made of a rectangular plate material that spans the entire vertical length of the guide surface portion 22a, but as long as it can engage with the guide groove 23, it can also be made of a member that is arranged only on a portion of the guide surface portion 22a in the vertical direction, such as a disk provided at the lower end of the vertical center line CL of the guide surface portion 22a. The convex member 26 is fixed to the outer surface of the guide surface portion 22a by known joining means such as welding or adhesive.

As shown in FIG. 12, the fixing surface portion 22b has one or more through holes 22c through which the anchor bolt 32 protruding from the upper surface of the precast deck 1B on the other side can be inserted. The convex guide member 22 is fixed to the precast deck 1B on the other side by inserting the upper end of the anchor bolt 32 through the through hole 22c and then screwing a nut from above.

As shown in FIG. 12, a spacer 33 of a specified thickness is placed between the fixed surface portion 22b and the other side of the precast deck 1B to prevent interference between the corner of the convex guide member 22 made of angle iron and the corner of the precast deck 1B.

The operation of lowering the precast deck using the guide members involves lowering the other precast deck 1B following behind while engaging the guide protrusion 24 of the convex guide member 22 with the guide groove 23 of the concave guide member 21. During this lowering, the concave guide member 21 and the convex guide member 22 engage, so that the other precast deck 1B being lowered is positioned in the bridge axis direction by the concave guide member 21 abutting against the convex guide member 22, and the guide protrusion 24 engages with the guide groove 23 to limit the swing to a specified range in the direction perpendicular to the bridge axis.

As shown in Figure 12, with the precast decks 1A and 1B facing each other with the joint section 2 in between, it is preferable to form the total thickness V of the concave guide member 21 and the convex guide member 22 that engage between the joint end faces of the precast decks 1A and 1B with dimensions that approximately match the width E of the joint section 2 (the separation width between the precast decks 1A and 1B). This makes it possible to align the width E of the joint section 2 without making any special adjustments, simply by installing the precast decks 1A and 1B while engaging these guide members, using the engaging concave guide member 21 and convex guide member 22 as spacers.

The guide members consisting of the concave guide member 21 and the convex guide member 22 can be provided on the joint end surfaces of the precast deck 1A, 1B in one or more places, but it is particularly preferable to provide them on both ends in the direction along the joint end surfaces of the precast deck 1A, 1B. In other words, it is preferable to provide them in a total of two places, one on each end of the joint end surfaces of the precast deck 1A, 1B in the direction perpendicular to the bridge axis. This makes it possible to align all the female joints 3 and male joints 4 simply by aligning the two places where the guide members 21, 22 are provided, thereby shortening the time required for alignment and significantly reducing the number of workers required for the lifting and lowering work, thereby reducing the risk of accidents caused by workers' hands and feet getting caught, and allowing the work to be performed safely.

As shown in Figure 12, it is preferable that the vertical engagement length A between the guide groove 23 of the concave guide member 21 and the guide protrusion 24 of the convex guide member 22 is greater than the vertical engagement length B between the groove engagement portion 6 of the female joint 3 and the fixing portion 8 of the male joint 4 as shown in Figure 5. The engagement length A is the vertical length from the position where the concave guide member 21 and the convex guide member 22 start to engage when the precast floor slab 1B on the other side is lowered to the completion of the lowering where the precast floor slab 1A on one side and the precast floor slab 1B on the other side face each other as shown in Figure 15(A). The engagement length B is the vertical length from the position where the fixing portion 8 of the male joint 4 starts to be inserted into the groove-type engagement portion 6 of the female joint 3 when the precast floor slab 1B on the other side is lowered to the completion position of the lowering where the precast floor slab 1A on one side and the precast floor slab 1B on the other side face each other. By making the engagement length A larger than the engagement length B, when the precast floor slab 1B on the other side is lowered to join the precast floor slabs 1A and 1B, as shown in Figure 15(A), the concave guide member 21 and the convex guide member 22 are engaged first, and the female joint 3 and the male joint 4 at this time are not engaged as shown in Figure 15(B), and then, by further lowering, the fixing portion 8 of the male joint 4 is inserted into the groove-type engagement portion 6 of the female joint 3. As a result, the precast deck 1B on the other side that is lowered and installed is reliably guided by the engagement of the guide members 21, 22, preventing collisions between the female joint 3 and male joint 4 and making it easy to adjust their positions. The difference in engagement length between the two (A-B) should be 5 to 100 mm, preferably 10 to 50 mm.

The gap between the guide groove 23 of the concave guide member 21 and the guide protrusion 24 of the convex guide member 22 in the direction perpendicular to the bridge axis may be constant over the entire length in the vertical direction, but it is preferable to form it so that it is large at the beginning of their engagement and gradually becomes smaller as the amount of engagement increases, as shown in Figures 13(A) and 14(A). This makes it easier for the guide protrusion 24 to engage with the guide groove 23 at the beginning of the engagement, and as the amount of engagement between the guide members 21 and 22 increases, the swing width in the direction perpendicular to the bridge axis becomes smaller, allowing the male joint 4 to be smoothly inserted into the female joint 3, and the female joint 3 and male joint 4 to be positioned in the center position.

In the illustrated example, a concave guide member 21 is attached to the precast deck 1A on one side that is installed first, and a convex guide member 22 is attached to the precast deck 1B on the other side that is subsequently lowered and installed. The guide groove 23 is formed in a tapered shape that widens toward the top, and the guide protrusion 24 is formed with a constant width over its entire length in the vertical direction, but the same effect can be achieved even if the guide groove 23 is formed with a constant width in the vertical direction and the guide protrusion 24 is formed with a tapered shape toward the bottom.

It is preferable that the gap dimension between the guide groove 23 and the guide protrusion 24 in the direction perpendicular to the bridge axis is smaller than the gap (room) between the female joint 3 and the male joint 4 in the direction perpendicular to the bridge axis at the hanging-down position where the fixing portion 8 of the male joint 4 begins to insert into the groove-type engagement portion 6 of the female joint 3. In other words, at the initial engagement of the convex guide member 22 and the concave guide member 21, it is preferable to form the gap dimension between the guide groove 23 and the guide protrusion 24 in the direction perpendicular to the bridge axis larger than the room between the female joint 3 and the male joint 4, but after further hanging, when the fixing portion 8 of the male joint 4 is inserted into the groove-type engagement portion 6 of the female joint 3, it is preferable that the gap dimension between the guide groove 23 and the guide protrusion 24 in the direction perpendicular to the bridge axis is smaller than the room between the female joint 3 and the male joint 4. This makes it easier for the concave guide member 21 and the convex guide member 22 to engage with each other in the initial stage of engagement, and when the female joint 3 and the male joint 4 are engaged, collisions between the female joint 3 and the male joint 4 are reliably prevented, allowing the male joint 4 to be smoothly inserted into the female joint 3.

(Method of joining precast deck 1A and 1B)
The method of joining the precast decks 1A and 1B will be explained with reference to Figures 15 to 17. Figure 15 shows the state in which the trailing precast deck 1B is in the middle of being lowered, and as shown in (A), shows the state in which the guide protrusion 24 of the convex guide member 22 begins to engage with the guide groove 23 of the concave guide member 21. Figure 15(B) shows the positional relationship between the female joint 3 and the male joint 4 at that time.

First, a concave guide member 21 is fixed to the precast deck 1A on one side, and a convex guide member 22 is fixed to the precast deck 1B on the other side.

Then, the precast deck 1B on the other side is lowered vertically onto the precast deck 1A on one side that has already been installed. The precast deck 1B is lowered while engaging the guide protrusion 24 of the convex guide member 22 with the guide groove 23 of the concave guide member 21, as shown in Figure 15.

As shown in Figure 16, the fixing portion 8 of the male joint 4 is inserted into the groove-type engagement portion 6 of the female joint 3, and the precast decks 1A and 1B are joined together. After that, the concave guide member 21 and the convex guide member 22 are removed.

After that, as shown in FIG. 17, the internal space IS of the groove-shaped engagement portion 6, the upper space US of the groove-shaped engagement portion 6, and the gap portion M between the precast floor slabs on one side and the precast floor slabs on the other side are filled with grout material 18. Note that concrete may be filled instead of the grout material 18.

(Second embodiment of the guide member)
Regarding the guide member of the second embodiment, the differences from the guide member of the above embodiment will be described, and the points that are not described in particular are the same as those of the guide member of the above embodiment, and the description of the guide member of the above embodiment will be applied as appropriate. The guide member of the second embodiment has a different shape of the concave guide member 21' compared to the above embodiment.

As shown in Figs. 18 and 19, the concave guide member 21' according to the second embodiment is formed to extend upward from the precast floor slab 1A on one side. Specifically, the concave guide member 21' is provided along the joint end surface of the precast floor slab 1A on one side and extends upward from this joint end surface, and is configured to include a member with a substantially T-shaped cross section consisting of a guide surface portion 21a' on whose outer surface the guide groove 23 is formed, and a fixing surface portion 21b' that extends perpendicularly from the middle portion of the guide surface portion 21a' and is arranged along the upper surface of the precast floor slab 1A on one side and has a fixing portion formed for the precast floor slab 1A. As an example of such a member, a general-purpose CT-shaped rope is preferably used.

On the outer surface of the guide surface portion 21a', plate materials 25', 25' are stacked and fixed on both sides of the vertical center line CL, each extending over almost the entire length in the vertical direction, and the guide groove 23 is formed by the separated portions of these plate materials 25', 25'.

By forming the concave guide member 21' to extend upward from the precast deck 1A on one side, as shown in Figure 20, when the concave guide member 21' and the convex guide member 22 begin to engage, the distance between the female joint 3 and the male joint 4 becomes larger, so that collisions between the female joint 3 and the male joint 4 are more reliably prevented.

(Other examples)
(1) In the above embodiment, the concave guide member 21 is attached to the precast deck 1A on one side that has already been installed, and the convex guide member 22 is attached to the precast deck 1B on the other side that is to be installed while being lowered, but the convex guide member 22 may be attached to the precast deck 1A on one side that is to be installed, and the concave guide member 21 may be attached to the precast deck 1B on the other side that is to be installed. In this case, it is preferable to form the guide groove 23 of the concave guide member 21 in a shape that widens downward so that the gap between the guide groove 23 of the concave guide member 21 and the guide protrusion 24 of the convex guide member 22 is large at the beginning of their engagement and gradually becomes smaller as the amount of engagement increases.

(2) In the above embodiment, a female joint 3 is provided on the joint end surface of the precast deck 1A on one side, and a male joint 4 is provided on the joint end surface of the precast deck 1B on the other side. However, three or more precast decks may be joined in a row. When joining three or more precast decks in a row, a female joint 3 is provided on one opposing surface of a single rectangular precast deck, and a male joint 4 is provided on the other opposing surface, and the following precast decks are joined in the same manner.

(3) In the above embodiment, the male joint 4 on the trailing precast deck 1B to be lowered is fitted from above into the female joint 3 on the preceding precast deck 1A that has already been installed. However, the opposite procedure may be used, in which the female joint 3 on the trailing precast deck 1B to be lowered is fitted from above into the male joint 4 on the preceding precast deck 1A that has already been installed. In this case, it is preferable that the female joint 3 is installed so that an open space that opens to the lower side is provided, and that the front vertical groove 5 is formed so that it extends continuously upward from the lower edge. In this case, the filling space of the grout material 18 becomes the internal space IS of the female joint 3, the lower side space of the female joint 3, and the gap portion M.

(4) In the above embodiment, the groove-type engaging portion 6 is formed in a box shape with an open top and a bottom, but it may be formed with a groove-type cross section that penetrates in the vertical direction with both the top and bottom open. In this case, both the top and bottom of the groove-type engaging portion 6 are left as open spaces, and after the male fitting 4 is joined, both the upper space US and the lower space of the groove-type engaging portion 6 are filled with grout material 18.

(5) As shown in Figures 1 to 3, on the precast deck 1A on one side and the precast deck 1B on the other side, multiple bridge axis direction reinforcing bars 15, 17 are arranged at intervals in the direction perpendicular to the bridge axis, at positions aligned with the bridge axis direction, over almost the entire length in the bridge axis direction. Furthermore, in addition to these bridge axis direction reinforcing bars 15, 17, reinforcing bars 19 perpendicular to the bridge axis, PC steel wires 20 perpendicular to the bridge axis, etc. may be arranged in a cross direction to provide firm reinforcement.

(6) The outer surfaces of the female joint 3 and the male joint 4 may be provided with uneven portions for fixing. It is preferable that the uneven portions have a form in which a plurality of convex or concave portions extending in a predetermined direction are arranged at intervals in a direction perpendicular to the direction in which the convex or concave portions extend.

1A, 1B... concrete precast deck, 2... joint, 3... female joint, 4... male joint, 5... vertical groove, 6... groove-type engagement part, 7... female joint anchor part, 8... anchoring part, 9... male joint anchor part, 15, 17... bridge axis direction reinforcing bar, 18... grout material, 19... bridge axis perpendicular direction reinforcing bar, 20... bridge axis perpendicular direction PC steel wire, 21... concave guide member, 22... convex guide member, 23... guide groove, 24... guide convex part, 25... plate material, 26... convex part, IS... internal space of groove-type engagement part, US... upper side space of groove-type engagement part, M... gap part

Claims (6)

A guide member used when joining concrete precast members,
The concrete precast members are embedded in the joint end surface of the concrete precast members on one side of the joint portion at a predetermined interval in the horizontal direction, with the vertical grooves facing the outside, the female joint being composed of a groove-shaped engagement portion having a groove-shaped cross section in a plan view and a female joint anchor portion extending to the rear of the groove-shaped engagement portion,
A male joint is embedded in the joint end surface of the other side of the joint at a predetermined interval in the horizontal direction on the joint end surface of the concrete precast member. The male joint anchor portion has a tip that protrudes outward, and a fixing portion that can be inserted into the groove-shaped engagement portion provided at the tip of the male joint anchor portion.
The guide member for joining concrete precast members is characterized in that the guide member is composed of a concave guide member having a guide groove extending in the vertical direction, and a convex guide member having a guide protrusion that can engage with the guide groove and move along the guide groove, which are arranged opposite each other on the joining end surface of the concrete precast members at a position where the female joint and male joint are not positioned. The guide member for joining concrete precast members according to claim 1, wherein the concave guide member and the convex guide member are provided at both ends in a direction along the joining end surface of the concrete precast member. A guide member for joining concrete precast members according to claim 1 or 2, in which the vertical engagement length A between the guide groove of the concave guide member and the guide protrusion of the convex guide member is set to be greater than the vertical engagement length B between the groove-type engagement portion of the female joint and the fixing portion of the male joint. A guide member for joining concrete precast members according to any one of claims 1 to 3, in which the gap between the guide groove of the concave guide member and the guide protrusion of the convex guide member is large at the beginning of their engagement and is gradually reduced as the degree of their engagement increases. A guide member for joining concrete precast members according to any one of claims 1 to 4, in which the guide member installed on the concrete precast member on one side extends upward from the concrete precast member. A method for joining concrete precast members using the guide member according to any one of claims 1 to 5,
a guide groove of the concave guide member and a guide convex portion of the convex guide member, while inserting the fixing portion of the male joint into the groove-type engaging portion of the female joint, thereby joining the concrete precast members, and then removing the concave guide member and the convex guide member, and filling the internal space of the groove-type engaging portion and the upper space and/or lower space of the groove-type engaging portion, and the gap between the concrete precast member on one side and the concrete precast member on the other side with grout material.

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